1、概述
(1)概念
springmvc的处理器拦截器类似于servlet中的过滤器filter,用于对处理器进行预处理和后处理。开发者可以自己定义一些拦截器(必须实现HandlerInterceptor)来实现特定的功能
(2)过滤器与拦截器
拦截器是AOP思想的具体应用。
过滤器:
servlet规范的一部分,任何javaweb工程都可以使用,在url-pattern中配置了/*之后,可以对所有要访问的资源进行拦截
拦截器:
拦截器是springmvc框架自己的,只有使用了springmvc框架的工程才能使用,拦截器只会拦截访问的控制器方法,如果访问的是jsp/html/css/images是不会进行拦截的
2、拦截器演示
(1)在web.xml中对前端控制器和中文乱码的处理进行配置:
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <!-- 前端控制器 --> <servlet> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!--绑定springmvc的配置文件--> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </init-param> <load-on-startup>1</load-on-startup><!--启动服务器即创建--> </servlet> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <filter> <filter-name>EncodingFilter</filter-name> <filter-class>pers.zhb.filter.EncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>utf-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>EncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
书写过滤器:
public class EncodingFilter implements Filter { public void init(FilterConfig filterConfig) throws ServletException { } public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { servletRequest.setCharacterEncoding("utf-8"); servletResponse.setCharacterEncoding("utf-8"); filterChain.doFilter(servletRequest,servletResponse); } public void destroy() { } }
(2)配置文件application:对视图解析器、拦截器等进行配置
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!--自动扫描包,让指定包下的注解生效,由IOC容器统一管理--> <context:component-scan base-package="pers.zhb.controller"></context:component-scan> <!--静态资源过滤,让Springmvc不处理静态资源,如css、js等--> <mvc:default-servlet-handler></mvc:default-servlet-handler> <!--使得注解生效--> <mvc:annotation-driven></mvc:annotation-driven> <!--视图解析器,前缀和后缀--> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver"> <property name="prefix" value="/"></property> <property name="suffix" value=".jsp"></property> </bean> <mvc:annotation-driven></mvc:annotation-driven> <mvc:interceptors> <mvc:interceptor> <mvc:mapping path="/*"></mvc:mapping><!--包括该请求下的所有请求--> <bean class="pers.zhb.config.MyInterceptor"></bean> </mvc:interceptor> </mvc:interceptors> </beans>
(3)拦截器:
public class MyInterceptor implements HandlerInterceptor { public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("preHandle qian"); return true;//return true的话执行下一个拦截器 } public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { System.out.println("postHandle hou"); } public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { System.out.println("afterCompletion qingli"); } }
(4)处理器:
@RestController public class TestController { @GetMapping("/test1") public String test1(){ System.out.println("123"); return "ok"; } }
(5)测试:
3、登录判断验证
(1)配置文件:applicationContext.xml,对视图解析器、拦截器进行配置
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!--自动扫描包,让指定包下的注解生效,由IOC容器统一管理--> <context:component-scan base-package="pers.zhb.controller"></context:component-scan> <!--静态资源过滤,让Springmvc不处理静态资源,如css、js等--> <mvc:default-servlet-handler></mvc:default-servlet-handler> <!--使得注解生效--> <mvc:annotation-driven></mvc:annotation-driven> <!--视图解析器,前缀和后缀--> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/"></property> <property name="suffix" value=".jsp"></property> </bean> <mvc:annotation-driven></mvc:annotation-driven> <mvc:interceptors> <mvc:interceptor> <mvc:mapping path="/user/**"></mvc:mapping><!--包括该请求下的所有请求--> <bean class="pers.zhb.config.MyInterceptor"></bean> </mvc:interceptor> </mvc:interceptors> </beans>
(2)页面:
起始页:
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>$Title$</title> </head> <body> <h1><a href="${pageContext.request.contextPath}/user/gologin">登录</a></h1> <h1><a href="${pageContext.request.contextPath}/user/main">首页</a></h1> </body> </html>
主页:
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <h3>首页</h3> <span>${username}</span> <p> <a href="${pageContext.request.contextPath}/user/goOut">注销</a> </p> </body> </html>
登录页:
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Login</title> </head> <!--在WEB-INF下的所有页面或资源,只能通过servlet或controller进行访问--> <body> <h1>登录页面</h1> <form action="${pageContext.request.contextPath}/user/login" method="post"> 用户名:<input type="text" name="username"> 密码:<input type="password" name="password"> <input type="submit" value="提交"> </form> </body> </html>
登录页面需要控制器的方法
(3)处理器:
import javax.servlet.http.HttpSession; @Controller @RequestMapping("user") public class LoginController { @RequestMapping("main") public String main(){ return "main"; } @RequestMapping("gologin") public String login(){ return "login"; } @RequestMapping("login") public String login(HttpSession session, String username, String password, Model model){ session.setAttribute("userInfo",username); model.addAttribute("username",username); return "main"; } @RequestMapping("goOut") public String goOut(HttpSession session){ session.removeAttribute("userInfo"); return "main"; } }
因为在WEB-INF下的所有页面或资源,只能通过servlet或controller进行访问,因此,需要书写相应的方法实现页面的跳转
(4)拦截器:
public class MyInterceptor implements HandlerInterceptor { public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { HttpSession session=request.getSession(); if(request.getRequestURI().contains("gologin")){ return true; } if(request.getRequestURI().contains("login")){ return true; } if(session.getAttribute("userInfo")!=null){ return true; } request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response); return false; } }
当有名为userInfo的session证明已经登录成功则不进行拦截,在跳转到登录页或者提交登录页信息的时候也不进行拦截。其他情况会被请求转发到登录页,如:未登录的时候在起始页点击首页。
(5)测试:
起始页:
登录页:
登录成功:
返回起始页点击首页:可以直接进入首页
点击注销后,返回起始页再次点击首页,跳转到登录页: